A harried prehistoric bird mom Ethel entrusts her precious, soon-to-hatch egg to Sid. When she recommends him to her neighbors – a condor mom, Cholly Bear and Gladys Glypto – business booms at his new egg-sitting service. However, dastardly pirate bunny Squint, who is seeking revenge on the herd, steals, camouflages and hides all the eggs. Once again, with Squint’s twin brother, Clint, assisting, Manny, Diego and the rest of the gang come to the rescue and take off on a daring mission that turns into the world’s first Easter egg hunt.

Manny, Sid, and Diego discover that the ice age is coming to an end, and join everybody for a journey to higher ground. On the trip, they discover that Manny, in fact, is not the last of the woolly mammoths.